A stacked-plate heat exchanger that comprises a plurality of rectangular plates through which a first fluid flows and that exchanges heat between a second fluid flowing around the outside of the plurality of plates and the first fluid has been known (see, Patent Document 1 below). In the plates of the heat exchanger described in Patent Document 1, each of the plates has a plurality of pressed-out portions formed by pressing out surfaces of the plates outwardly in a protruding manner so as to form convexes. Each of the pressed-out portions is formed such that a longitudinal direction of the pressed-out portion is along a diagonal line of the plate.
The plate of the heat exchanger described in Patent Document 1 is arranged such that a long side of the plate is orthogonal to a flow direction of the second fluid; the plates are fixed such that respective protruding surfaces of the pressed-out portions abut each other on a flow path of the second fluid. With this configuration, the pressed-out portions, the protruding surfaces of which abut each other, function as a turbulent flow generator for creating a turbulence by inhibiting a linear flow of the second fluid.
Consequently, the heat exchanger described in Patent Document 1 can increase heat transfer efficiency on an outer surface of the plate, thereby improving heat exchange efficiency.